SSDs have effectively zero random read access overhead when compared to traditional drives, because the overhead is a couple of orders of magnitude smaller. Also for SATA connected SSDs the effect of this read latency is reduced by bottlenecks elsewhere.
For the common home/office/other user the difference between zero and effectively zero is, well, effectively zero, so the two easily conflate. It isn't so much a myth as a convenient simplification.
(The fact that there is still latency is very easy to show though - just throw something like crystaldiskmark at an SSD and show the measured throughput difference between the sequential and random tests.)
For NVMe drives where the bottlenecks of SATA are removed the difference starts to become more noticeable, and on any SSD random write latency is more significant than random read latency, but NVMe has only recently become common for the general user and the tests that people usually look at are random read not random write as for those common users this is the most significant measure in terms of how it will affect their day-to-day use patterns.
